I just hooked up my Commodore 64 after it being in a box for many years and the blue screen it displays is blue and all, but the text that's on the screen wiggles and dances all funky so you can't read what the characters are. I loaded up Bubble Bobble (from memory knowing how to load stuff so not needing to see what I've typed), and it worked all right except the graphics are funky so you can't really play it. The sound is fine, just the graphics are goofy. Seems only the sprites and ASCII are affected because the border on the blue screen doesn't wiggle and dance.
The dancing ASCII is side to side, not up and down. For example, the cursor jumps left and right about 6 characters.
The ASCII wiggles seem localized to each character space (each character does it's own particular wiggle) and make it impossible to disinguish between characters unless you know what's supposed to be there and can figure it out anyway. Like the asterisks on the screen when you turn it on.
How to fix? :-? :-(